How to Change the Oil in a 1995 Yamaha YZ125: A Complete MotoSport.com Guide

Shop parts for a 1995 Yamaha YZ125 Dirt Bike.

Regular oil changes are crucial to keeping your 1995 Yamaha YZ125 running at its best. Unlike four-strokes, your YZ125—s oil change means servicing the transmission (gear) oil, not engine oil, since it—s a two-stroke. This guide will walk you through the process, call out tools you—ll need, and provide tips specific to this model. Let—s keep your ride performing at its peak.

Tools and Supplies Needed

  • Socket wrench with 12mm socket
  • 4mm Allen wrench (for oil check bolt)
  • Measuring cup (marked in milliliters/US quarts)
  • Drain pan (for catching used oil)
  • Oil funnel (ideally long and narrow)
  • New transmission oil (SAE 10W-40 recommended, 0.69 US qt/660 ml per change)
  • Replacement aluminum washer for the drain bolt (not essential every change, but recommended)
  • Clean rags
  • Torque wrench

Recommended Oil for 1995 Yamaha YZ125

  • Yamalube 4, SE SAE 10W-30 or 10W-40 motor oil
  • Other reputable brands formulated for wet clutches are acceptable; the oil should meet API SG (or higher) and JASO MA standards
  • Capacity: 0.69 US quarts (0.66 liters/660 ml)

Step-by-Step Oil Change Process

  • Warm up the bike. Briefly start and idle the engine for a few minutes (do not rev hard). This warms the oil, allowing it to drain more efficiently. Shut the engine off and allow it to sit for five minutes to settle the internal oil.
  • Stabilize and prepare. Set your YZ125 on a level surface (center stand or bike stand is best) and make sure it–s upright. Place the drain pan under the crankcase. Remove the oil fill cap (top of transmission case) to help oil flow during draining.
  • Remove the drain bolt. Using a 12mm socket wrench, carefully remove the drain bolt located at the bottom of the crankcase. Allow all the oil to drain fully into your pan.
    • Pro tip: Replace the aluminum washer on the drain bolt if it appears damaged or squashed. This helps prevent leaks.
  • Reinstall the drain bolt. Once drained, install the drain bolt (with washer). Tighten to 14 ft-lbs (20 Nm) using a torque wrench. Avoid over-tightening, which can strip threads.
  • Measure and add new oil.
    • Using your measuring cup, pour in exactly 0.69 US quarts (660 ml) of recommended oil via a funnel. Go slow to avoid spills.
    • Model specific tip: The fill opening is beneath the exhaust header, so a long funnel helps get the oil in cleanly and easily.
  • Check the oil level. On 1995 and similar YZ125 models, you can check the oil level using the side check bolt (accessible with a 4mm Allen wrench).
    • Remove the check bolt briefly after adding oil. If oil dribbles out, your level is spot-on. If not, add a small amount more oil and check again until you see oil.
  • Reinstall fill and check bolts. Ensure both the fill and check bolts are properly secured. Wipe off any excess oil around the case.
  • Final check for leaks. Wait several minutes, inspect the drain and fill areas for any sign of leakage. Start the engine and look again after the bike runs for a couple of minutes.
  • Dispose of the old oil responsibly. Auto parts stores and recycling centers typically accept used oil. Never dump it in the trash or drains.

Special Call-outs for 1995 Yamaha YZ125 Owners

  • Only change the transmission/gear oil. The YZ125 is a two-stroke—engine lubrication relies on pre-mix in your fuel, not an oil sump.
  • Care with the fill amount–overfilling can cause shifting issues, underfilling can accelerate wear. Stick to the specified 0.69 qt (660 ml).
  • Always use oil specified for wet clutches. Automotive oils often have friction modifiers that can cause clutch slippage in a motorcycle.
  • The 1995 model shares its basic transmission and oil procedure with YZ125s from 1994–2001—the above specs and steps apply for your bike.
  • If you spot milky oil on draining, check for coolant leaks in the crankcase–this is a sign of a bad seal or gasket.

Summary: Keep Your YZ125 Shifting Smooth

Changing the oil in your 1995 Yamaha YZ125 is a quick, crucial job. Following this guide will protect your clutch and gears, keeping you ready for the track or trails. Get all your oils, tools, and parts at MotoSport.com—we—ll help keep you riding all season long.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.